THE BRAIN AND ITS VASCULATURE is tightly integrated multidisciplinary effort involving 25 investigators from 8 departments of the Washington University Medical Center [Radiology, Psychology, Medicine, Pediatrics, and the Center for Biomedical Computing]. This program represents the continuation of a 24 year quest for an understanding of the vasoculature of the human brain and its relationship to the function of the brain in health and disease. Because of the intimate relationship between the brain vasculature and brain function, studies of the vascular and metabolic responses to physiological activation offer a unique window to safely study the functional organization of the living human brain. The importance of such an approach has been increasingly appreciated with the development of safe imaging techniques that permit the detection of local vascular and metabolic responses with a precision of a few millimeters. In this program we seek to bring together all of the elements necessary to successfully undertake studies of the human brain using such an approach. Our strategy is to combine within one program studies of advance imaging strategies [Cores 2,3,4] with detailed studies of the microvasculature and its relationship to the neuronal environment, studies of the organization and importance of substrate delivery to the brain in health and disease and studies of the relationship between brain vascular responses and brain electrical activity. These efforts will not only provide valuable new scientific information in their own right , but will also stand in support of our efforts to study the highest levels of information processing in the human brain and the recovery processes that take place after injury from stroke.